FROM THE HINDU SCRIPTURES   
The Bhagavad Gita 18   

Krishna:  
Because I love thee well, I will speak to thee words of salvation.  Give thy mind to me, and give me thy heart, and thy sacrifice, and thy adoration.  This is my Word of promise;  thou shalt in truth come to me, for thou art dear to me.  Leave all things behind, and come to me for thy salvation.  I will make thee free from the bondage of sins.  Fear no more.  Hast thou heard these words, Arjuna, in the silent communion of thy soul?  Has the darkness of thy delusion been dispelled by thine inner Light?  

Arjuna:  
By thy grace I remember my Light, and now gone is my delusion.  My doubts are no more, my faith is firm; and now I can say 'Thy will be done.'  

FROM THE BUDDHIST SCRIPTURES   
The Dhammapada   

The followers of Buddha Gotama are awake and forever watch; and ever by night and by day they remember the Truth of the Law.  The followers of Buddha Gotama are awake and forever watch; and ever by night and by day they remember the holy brotherhood.  The followers of Buddha Gotama are awake and forever watch; and ever by night and by day they find joy in love for all beings.  The followers of Buddha Gotama are awake and forever watch; and ever by night and by day they find joy in supreme contemplation.  

FROM THE ZOROASTRIAN SCRIPTURES   
The Zend Avesta of Zarathustra   

Inspired by Thy Benevolent Mind, do I approach Thee and beseech Thee to grand me as a bountiful gift, those attainments to be derived from the Divine Order of Asha.  O Thou Cosmic Order!  And Thou Universal Mind!  I will worship Thee Ahura Mazda because of whom the Creative Mind within us is causing the Imperishable Kingdom to progress.  

So long as I be able and may have the power, so long will I teach the people concerning those deeds to be done by them with faith toward Mazda, and in the desire for the coming of the Cosmic Order of Asha into their souls and their bodies....And do Thou, O Mazda!  O Great Creator!  Come to me with Thy Creative Mind!  And do Thou, Who bestoweth gifts through Thy Cosmic Order, bestow alike, long-lasting gifts upon us,  that this life may be spend aright!  

FROM THE JEWISH SCRIPTURES   
Psalm 23   

The Lord is my shepherd; I shall not want.  
He maketh me to lie down in green pastures;  he leadeth me beside the still waters.  He restoreth my soul.  
He leadeth me in the paths of righteousness for his name's sake.  
Yea, though I walk through the valley of the shadow of death, I will fear no evil;  for thou art with me;  thy rod and thy staff they comfort me.  
Thou preparest a  table before me in the presence of mine enemies;  thou annointest my head with oil;  my cup runneth over.  Surely goodness and mercy shall follow me all the days of my life;  and I will dwell in the house of the Lord for ever.  

FROM THE CHRISTIAN SCRIPTURES;   
Romans 5  

Being justified by faith, we have peace with God through our Lord Jesus Christ:  by whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God.  
And not only so, but we glory in tribulations also:  knowing that tribulation worketh patience, experience;  and experience, hope:  and hope maketh not ashamed, because the love of God is shed abroad in our hearts by the Holy Ghost which is given unto us.  
And not only so, but we also joy in God through our Lord Jesus Christ, by whom we have now received the atonement.  

FROM THE ISLAMIC SCRIPTURES   
The Koran   

By the light of day, and by the fall of night, your Lord has not forsaken you, nor does he abhor you.  The life to come holds a richer prize for you than this present life.  You shall be gratified with what your Lord will give you.  

FROM THE GAYAN, VADAN AND NIRTAN OF HAZRAT INAYAT KHAN   

Optimism is the result of love.  

You will find reasons, whether you want to be pessimistic or optimistic, to support your view.  

It is the spirit of hopelessness that blocks the path of man and prevents his advancement.  

The essence of life is hope.  If we hope to be better, we shall become better.  

The shade adds to the light as zero adds to the number.  

Put your trust in God for support and see His hidden hand working through all sources.  
In the influence that controls a situation the hand of God is seen.  
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Additional Material FROM HAZRAT INAYAT KHAN
 

 Hope is a quality sometimes dependent on its object, sometimes independent of it, and these two different aspects of hope are the cause of two different natures, the optimistic and the pessimistic.

   
 When the dependent nature is developed it makes man a pessimist, and when hope stands alone, without dependence, this develops optimism.  The optimistic person compared to the pessimistic may seem blind, and no doubt, he is at times blind.  But without doubt, as blind people develop a faculty of doing things without sight which people with seeing eyes cannot do, so the optimist can accomplish things without knowing how or why.  Hope cannot be called sureness of certainty, but it is a feeling which, almost by its own force, may bring sureness and certainty.  Hope dependent upon reason is weak, and the more dependent the weaker it is.  No doubt hope together with reason is strong, perhaps stronger than hope alone, but in proportion as reason supports hope, so hope depends on reason, and as in many cases in life reason cannot reach the object of hope, hope then sinks.

   
 In fact hope is more than a faculty or a quality, hope may be called the substance of life.  Wise and foolish, rich and poor, all live in some hope.  Hope can prolong life and lack of hope can shorten it.  The joy that one gets from hope is greater than the joy that comes from the possession of the object hoped for.  Therefore there is a Sanskrit saying that Brahma in the creation took honey from all the flowers and that this honey was hope.  The interpretation is that out of all things that are beautiful and that give joy and happiness the essence is taken and that essence is hope.

   
 Hope is strengthened by reason, but it stands on the foundation of patience, for it is possible that in spite of all reasons a person may completely give up hope, if patience is lacking.  If I used the poetical expression that the rocks and trees are standing in the deserts and forests resting in hope, that would be no exaggeration, because to the eyes of the mystic every aspect of life shows that it is standing in hope.  This can be better seen in the life of human beings, because every person seems to be waiting from day to day and from hour to hour for something to come that he is hoping for.  The loss of hope is worse than the loss of life, and provided that hope stands by man's side, though no one else stands by him it does not matter.
   
GATHA 1, METEPHYSICS, HOPE - HAZRAT INAYAT KHAN
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Spirit of Optimism

 There is no such thing as impossible.  All is possible.  Impossible is made by the limitation of our capacity of understanding.  Man, blinded by the law of nature's working, by the law of consequences which he has known through his few years life on earth, begins to say, "This is possible and that is impossible."  If he were to rise beyond limitations, his soul would see nothing but possible.  And when the soul has risen high enough to see all possibility, that soul certainly has caught a glimpse of God.

   
 They say God is all-mighty; and I say, God is all-possible.  Possibility is the nature of God, and impossibility is the art of man.  Man goes so far, and cannot go any further.  Man makes a flower out of paper, giving it as natural a color as possible, yet he says it is not possible to make it fragrant, for he has his limitations.  But God, Who is the Maker of the flower and who is the Giver of the fragrance, has all power, and man, who is weakened by his limitedness, becomes more and more limited the more he thinks of it.  In this is created the spirit of pessimism.  

 Man who is conscious of God Almighty, and who in the contemplation of God loses the consciousness of his own self, inherits the power of God, and it is in this power and belief that the spirit of optimism is born.
   
GITHA 2 SPIRIT OF OPTIMISM - HAZRAT INAYAT KHAN